AIRBUS A320 NEO ONLINE COURSE STUDENT BOOK 12 MODULE 12

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AIRBUS A320 NEO STUDENT BOOK 12 The Airbus Single Aisle family pneumatic system supplies High Pressure (HP) air for: - Air conditioning,

Both BMCs exchange data. In this NEO configuration, one BMC can control & monitor both sides when the other BMC fails.

- Wing ice protection, - Water Tank pressurization, - Hydraulic reservoir pressurization, - Engine starting, - Fuel tank Inerting system. High Pressure air can be supplied from three sources: - The Engine Bleed system, - The APU, - A HP Ground Air source.

The pneumatic system operates electro-pneumatically and is controlled and monitored by 2 Bleed Monitoring Computers (BMC 1 & 2). There is one BMC for each engine bleed system.

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AIRBUS A320 NEO STUDENT BOOK 12 The Engine Bleed Air is pressure and temperature regulated before it supplies the pneumatic system. Air is bled from an Intermediate Pressure (IP) stage (HP3) or the HP8 stage with the High Pressure Valve (HPV) which is used for the pneumatic regulation. The IP check valve gives protection to the IP stage from reverse flow when the HP valve is open.

BMCs are Dual Channel computers. Each BMC channel A is a full digital channel embedding all the control and monitoring functions. Channel B is a hardware part and back-up channel able to detect system overtemperature. For the monitoring, the BMCs read pressure transducers (upstream / downstream of the PRV), Precooler Differential Pressure and downstream temperature with the Bleed.

Note: The Engine Bleed Air System (EBAS) uses electro-pneumatic valves.

The left and right bleed systems are connected by a crossbleed duct. A Crossbleed Valve is used for their interconnection or isolation.

The HP bleed is only used when the engines are at low power and for engine efficiency the High Pressure Valve (HPV) is kept closed during cruise

The APU is mainly used for bleed air supply on the ground for air conditioning and for engine start.

The Pressure Regulating Valve (PRV) regulates the bleed air pressure.

But APU BLEED air can also be used in flight, but limited in altitude.

The PRV is used as a protective shut off valve when the parameters are abnormal. In case of EBAS electrical failure, the PRV operates in back-up pneumatic mode.

The APU bleed supply is connected to the left side of the crossbleed duct. On the ground, an HP Ground cart can be connected to the left side pneumatic system. The Crossbleed valve has to be opened to supply the right side

An Overpressure Valve (OPV) is installed downstream of the bleed valve to give protection to the system if an overpressure condition occurs. On this PW Engine the OPV is installed in the engine core. The Fan Air Valve (FAV) modulates Fan discharge air through an air-to-air heat exchanger called "Precooler" to reduce the Bleed temperature.

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AIRBUS A320 NEO STUDENT BOOK 12 Leak detection loops are installed along the hot air supply ducts of the pneumatic system. The loops are made of multiple sensing elements connected in series to the BMCs Overheat Detection System (OHDS).

If a leak is detected, a signal is sent to the BMC 1 or 2 which automatically isolates the affected area by closing the crossbleed valve and shutting off the engine bleed on the affected side. The leak detection system is organized into three loops. Here are the loops and the protected areas: - Pylon: dual loop from the precooler to the wing leading edge.

- Wing: dual loop from wing leading edge, including the wing air inlet supply, and belly fairing (cross bleed duct, pack supply ducts and APU forward supply duct). - APU: single loop at APU aft supply duct (left hand side of the fuselage) from APU firewall to wheel well .

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AIR CONDITIONING BAY LOOPS A AND B

COMMOM DUCT

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AIRBUS A320 NEO STUDENT BOOK 12 Controls for the pneumatic system are part of the AIR COND panel and are operated from the overhead panel

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AIRBUS A320 NEO STUDENT BOOK 12 The pneumatic system indications are displayed on the lower part of the ECAM BLEED page: - HPV, PRV positions with delivered bleed pressure and temperature, - APU bleed and crossbleed status

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AIRBUS A320 NEO STUDENT BOOK 12 Using the Multipurpose Control and Display Unit (MCDU), you can have access to the Centralized Fault Display System (CFDS) fault messages of the PNEUMATIC system. BMC1 and BMC2 Built-In Test Equipment (BITE) is standard type 1.

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AIRBUS A320 NEO STUDENT BOOK 12 When you do work on the aircraft, make sure that you obey all the Aircraft Maintenance Manual (AMM) safety procedures. This will prevent injury to people and / or damage to the aircraft. Here is an overview of the main safety precautions related to the pneumatic system.

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AIRBUS A320 NEO STUDENT BOOK 12 The primary components of the pneumatic system are installed on the engines and in the pylons. The pressure regulation components on the engines are the: - Engine HPV, - Engine BLEED PRV - OPV, - Bleed Monitoring Pressure Sensor (BMPS), - Bleed Pressure Sensor (BPS), - Differential Pressure Sensor (DPS). To get access, open the right fan cowl and thrust reverser cowl.

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AIRBUS A320 NEO STUDENT BOOK 12 The temperature regulation components are in the pylons: - the FAV,

- the Precooler, - the Bleed Temperature Sensor (BTS).

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AIRBUS A320 NEO STUDENT BOOK 12 The Crossbleed valve is in the forward section of the lower fuselage belly fairing area. The access to the HP ground connector is through a small access door on the lower fuselage belly fairing. The APU supply duct is installed along the left hand side of the fuselage to the wheel well area and is connected to the crossbleed duct in the forward belly fairing area.

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AIRBUS A320 NEO STUDENT BOOK 12 The Engine Bleed Air System (EBAS) supplies pressure and temperature regulated airflow from each engine to the air system users. During normal operation, each engine bleed system is isolated from adjacent system by the Crossbleed valve; except during 2nd engine starting using air bled from 1st started engine, Crossbleed valve opened or under APU Bleed. The pressure regulation system is controlled and monitored by two Bleed Monitoring Computers (BMCs). As compared to A320 CEO, the NEO engine has higher bleed air temperatures during High Pressure (HP) operation, lower air pressure during Intermediate Pressure (IP) operation, lower fan pressures for cooling air flows Supply and limited space for installation due to new pylon configuration. To achieve better performance requirements a new electro-pneumatic bleed air system is designed for A320 NEO

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AIRBUS A320 NEO STUDENT BOOK 12 Normally BMC 1 Channel A does all the control and monitoring of the LH EBAS and BMC 2 Channel A the RH EBAS. Each BMC channel A controls torque-motor and solenoid for the electropneumatic valves, monitors sensors. As both BMC interface, each one is capable to control both sides. The channel B is a fully hardware part able to detect the system overtemperature: Electrical Protection Function (EPS). This detection is fully independent from software part. Each BMC reports the failures independently of each other.

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AIRBUS A320 NEO STUDENT BOOK 12 An Intermediate Pressure Check Valve (IPCV) lets air to be bled from the engine IP stage. It is closed when air is bled from HP stage. The purpose of this IPCV is to allow the flow from IP stage and avoid the reverse flow from either the HP port or the pneumatic manifold.

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AIRBUS A320 NEO STUDENT BOOK 12 The Pressure Regulating Valve (PRV) is a 4 inch diameter butterfly valve, installed downstream of the IPCV and HPV.

It operates pneumatically. The OPV, normally in spring-loaded open position will be fully closed if bleed pressure reaches 90 psig. The valve has a manual override and test port for pneumatic test in-situ.

It regulates the pressure of the bleed air at 42 ± 2 psig in normal dual bleed operation (50 ± 2 psig in single bleed operation). Its setting is modulated by the electric command on the torque-motor. When the torque-motor is de-energized, the PRV is commanded to the full closed position.

When the torque-motor is energized but without pressure, the PRV stays closed. With the torque-motor energized, the minimum upstream muscle pressure needed to operate the valve is 15 psig. The PRV operates as a shut off valve when abnormal conditions occur. In case of electrical failure of the EBAS, pressure control is ensured by the PRV in back-up pneumatic control mode. The valve has a manual override and test port for pneumatic test in-situ. The Overpressure Valve (OPV) downstream of the PRV in the engine core, protects the system against damage if overpressure occurs.

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AIRBUS A320 NEO STUDENT BOOK 12 The Bleed Monitoring Pressure Sensor (BMPS) is used to perform bleed port switching function. It is also used to estimate the position of the HPV butterfly and to monitor the HPV and the PRV.

The Bleed Pressure Sensor (BPS) is installed downstream the PRV. It provides to BMC the actual bleed air pressure delivered through the PRV. This sensor is also used by the BMC for system monitoring (overpressure and low pressure alarms) and to monitor the position of the OPV butterfly. The Differential Pressure Sensor (DPS) ensures the reverse flow protection by sensing the differential pressure between Precooler hot side inlet and outlet. It also provides to the BMC an indication of the PRV and OPV position

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AIRBUS A320 NEO STUDENT BOOK 12 The dual Bleed Temperature Sensor (BTS) installed downstream the Precooler provides to the BMC the actual EBAS temperature. The BMC uses EBAS temperature to position the Fan Air Valve (FAV). The wiring connected to channel A of the BTS is fully segregated from the wiring connected to channel B. Both BMCs interchange temperature measurements and can carry out both sides temperature regulation. This dual sensor is also used by the BMCs for system monitoring (overtemperature and low temperature alarms). NOTE: Channel B of one BMC is connected to Channel A of the other BMC, so that in case of loss of temperature monitoring and control in Channel A of one side, the opposite controller can take over control of the whole EBAS.

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AIRBUS A320 NEO STUDENT BOOK 12 The FAV pneumatically regulates the fan airflow to the Precooler for bleed air temperature regulation. The FAV butterfly valve actuator rod is adjusted by the BMC via a torque motor servo-control depending on BTS input. The BMC set point is 200°C (392°F) in normal operations and 160°C (320°F) in Climb and Hold with 2 bleeds and Wing Anti-Ice (WAI) off. With no electrical power and enough muscle pressure, the FAV valve is fully open. The valve has a test port for pneumatic test. The Precooler is a stainless steel and nickel alloy air-to-air heat exchanger. It cools down the hot air supplied from the engine HP compressor stage by a heat exchange process with cooling flow taken from the engine fan in-situ.

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AIRBUS A320 NEO STUDENT BOOK 12 The PRV operates as a shut-off valve. It is commanded to close in the following conditions:

- HPV failed open - Dual BTS channels failed.

- Over-temperature downstream of the Precooler (BTS): 257°C (495°F) < T ≤ 270°C (518°F) during 55s, 270°C (518°F) < T ≤ 290°C (554°F) for 15s, T > 290°C (554°F) for 5s. - Overpressure downstream of the PRV > 60 ± 3 psig at BPS, - Engine fire (consequence of crew action on the ENG FIRE P/B), - Leak detection in pylon/wing/fuselage ducts surrounding areas - APU bleed valve not closed & APU BLEED P/B selected: Depending on the Crossfeed Bleed Valve (CBV) position, only one PRV (left engine PRV if CBV is closed) or both (if XBleed is open) - Reverse flow detected by DPS, - ENG BLEED P/B selected OFF or ENG not running, - Associated Starter Air Valve (SAV) not closed

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AIRBUS A320 NEO STUDENT BOOK 12 The pneumatic system uses 2 identical controllers with a microprocessor and command channel A and a back-up channel B. Each channel is supplied by a different 28V DC bus bar.

Both Bleed Monitoring Computers (BMCs) will work as MASTER/SLAVE so long as the ARINC429 cross communication is working properly. If one ARINC429 bus is lost from one BMC to the other, the BMC receiving no data will take over control and would inform to the opposite BMC.

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BMC

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AIRBUS A320 NEO STUDENT BOOK 12 The Propulsion Control System (PCS) informs both BMCs via both Engine Interface Units (EIUs) when engines start/run. The Electronic Engine Control (EEC) will need information relative to the Aircraft Environmental Control System (ECS) from the EIU ARINC data bus as system bleed pressure, bleed and anti-ice configuration. The EIUs receive positions of ENG BLEED P/Bs ON, APU BLEED P/B OFF, Crossbleed valve status

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AIRBUS A320 NEO STUDENT BOOK 12 The up and down data loading system is an interface between the onboard computers as BMCs and the ground-base data processing stations. For data loading purposes, the BMC 1 Channel A is connected to Data Loading Routing Box (DLRB). The BMC 2 Channel A will be loaded through BMC 1 Channel A. The BMC 2 will be uploaded through the crosstalk bus from the BMC 1 once the BMC 1 has been fully uploaded from the data loader.

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AIRBUS A320 NEO STUDENT BOOK 12 The BMC inform the Air Conditioning System Controller (ACSC) on the precooler outlet temperature for pack flow calculation. The bleed pressure Sensor (BPS) and the wired Crossbleed valve position are used for Pack Inlet Pressure Sensor (PIPS) monitoring. The BMC send a discrete input of its Pressure Regulating Valve (PRV) position. Another discrete signal informs about the precooler delivered bleed pressure. The ACSCs input the BMCs for Pack 1/2 P/B SW position, Pack Inlet Pressure and wing anti-ice valves position.

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AIRBUS A320 NEO STUDENT BOOK 12 The BMCs 1 and 2 transmit ARINC signals to the System Data Acquisition Concentrator (SDAC) for monitoring, fault indication, warning and data recording purposes by the Flight Warning Computer (FWC), Electronic Instrument System (EIS) and Digital Flight Data Recording System (DFDRS). The Centralized Fault Display Interface Unit (CFDIU) is connected to the BITE of the BMCs to centralize the pneumatic system data for maintenance via the Multipurpose Control and Display Units (MCDUs), printer and Aircraft Communication Addressing and Reporting System (ACARS).

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AIRBUS A320 NEO STUDENT BOOK 12 The APU/Electronic Control Box (ECB) system sends to the Engine Bleed Air System EBAS/BMC the information about APU bleed valve position in order to command the PRV to close when APU BLEED P/B is ON.

The EBAS transmits to the ECB information related to the APU Bleed Valve open Command in order to provide APU Bleed valve control in when APU flow is required.

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AIRBUS A320 NEO STUDENT BOOK 12 The leak detection system is used to detect leaks in the vicinity of the packs, wings, pylons and APU hot air ducts. There are two independent loops as redundancy in both pylons and both wing sides. The APU hot air duct is monitored by a single loop. Protected areas with double loop for: - Engine 1 and Engine 2 pylons, - RH wing and pack 2, - LH wing, pack 1 and mid fuselage APU duct. Protected areas with single loop for: - APU duct. NOTE: Each loop consists of sensing elements connected in series. Both extremities of the overheat detection loop are connected to the BMC.

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Both Bleed Monitoring Computers (BMCs) permanently receive signals from the leak detection loops primarily tested at power-up. They exchange data via an ARINC bus for the double loop detection. Each BMC channel A normally controls its side engine bleed air system, so monitors the OverHeat Detection System (OHDS). NOTE: The wing and pylon loops A are connected to one BMC and wing and pylon loops B to the other BMC. The crosstalk bus allows wing leak warnings to be activated through an AND logic. The APU loop is connected to BMC 1 only.

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The ENG BLEED FAULT light comes on when a leak is detected by the wing loops A and B or by the pylon loops A and B. The APU BLEED FAULT light comes on when an APU duct leak is detected. When an overheat condition is detected by both loops, the following alerts are generated for the affected zone:

A detected leak will close associated valves, as shown on the table. These valves are automatically controlled to close if they were open. NOTE: APU and cross bleed (X-BLEED) valves do not close during Main Engine Start (MES)

- AIR ENG 1(2) LEAK for a leak/overheat detected in the Pylons, - AIR L(R) WING LEAK for a leak/overheat detected in the Wings, - AIR APU LEAK for a leak/overheat detected in the APU line, -

AIR APU LEAK [APU LEAK FED BY ENG] for a leak/overheat detected in the APU line and the leak is automatically isolated.

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A new warning alert has been introduced on the A320neo, the AIR BLEED LEAK to isolate a bleed leak in the opposite pylon to the operative bleed with manually open Crossbleed Valve.

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The failure of a single loop for Pylon or Wing is identified by a MAINTENANCE message displayed on the STATUS SD page.

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Dual engine loop failure is identified by the AIR ENG 1(2) LEAK DET FAULT and is NO GO.

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If one BMC is failed, the other BMC takes over monitoring of the bleed system and triggers the ECAM warnings.

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The aircraft dispatch is for 10 days with the BMC 1 inoperative for non-ETOPS operations provided that the Engine 1 Bleed Air System (EBAS 1) is considered inoperative and the APU leak detection loop is considered inoperative.

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AIR ENG 1 LEAK AIR ENG 2 LEAK AIR BLEED LEAK AIR ENG 1 BLEED FAULT AIR ENG 2 BLEED FAULT AIR APU LEAK

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